Poking around Google Data Explorer I reacquainted myself with an interesting fact: though the teen birth rate in Bangladesh is greater than that in Pakistan, the total fertility rate is far lower. The disjunction has emerged over the last generation, as Bangladesh’s TFR has dropped much faster than Pakistan’s. To the left you see a scatter plot, which shows teen fertility rates (age 15-19) as a function of total fertility rates. I’ve labeled a few nations, and also added the color coding by region. It is notable that the nations above the trend line seem to be Latin American, while those below are disproportionately Middle Eastern. That means that Latin American nations have higher teen fertility in relation to their total fertility, while Middle Eastern nations have lower teen fertility in relation to their total fertility. Sweden actually has a rather high fertility rate in relation to its teen birth rate. The expectation is generated by world wide patterns, so I thought I’d look more closely at the original data sets from the The World Bank. All the data is from 2008. The teen birth rates are per 1,000 of teens in the age range, with TFR’s are per woman.

My contention is this: those nations with high overall fertility despite low teen fertility rates indicate an ideological or operational pro-natalist cultural stance. That means that mature adult women in marriages are presumably having many children. The high teen fertility rates in Bangladesh vis-a-vis Pakistan is probably simply due to lower aggregate development (Pakistan is still higher up on the HDI ranking, though the gap is closing).

Below are some charts. First, a plot with lines of best fit (as generated by R’s loess function). Then, absolute deviations from the line of best fit as a function of fertility. Also, percentage deviations from the line of best fit as a function of fertility. I provide the weighted trend line, but rely on the unweighted fit for the rest of the charts.

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Next, let’s compare percentage and absolute deviation from the trend line on the same plot.

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Finally, a table with the “top 15.”

Country

Teen births/1,000

TFR

Population

Deviation

% Deviation

Top 15 absolute deviation above the trend line

Nicaragua

112.09

2.72

5667325

61.11

54.52

Dominican Republic

108.18

2.65

9952711

58.93

54.48

Brazil

75.07

1.88

191971506

45.83

61.05

Nepal

98.51

2.9

28809526

44

44.67

Venezuela

89.67

2.54

27935000

43.28

48.27

Cape Verde

93.36

2.73

498672

42.15

45.14

El Salvador

82.22

2.32

6133910

41.28

50.2

Ecuador

82.6

2.56

13481424

35.69

43.21

Costa Rica

66.9

1.96

4519126

35.47

53.02

Honduras

92.26

3.26

7318789

35.47

38.44

Panama

81.95

2.55

3398823

35.3

43.07

Jamaica

76.62

2.39

2687200

33.94

44.3

Gabon

88.6

3.31

1448159

31.68

35.76

Colombia

73.75

2.43

45012096

30.13

40.85

Mexico

64.33

2.1

106350433.7

29.21

45.4

Top 15 percentage deviation above the trend line

Brazil

75.07

1.88

191971506

45.83

61.05

Cuba

45.36

1.51

11204735

26.13

57.6

Bulgaria

41.6

1.48

7623395

23.18

55.71

Nicaragua

112.09

2.72

5667325

61.11

54.52

Dominican Republic

108.18

2.65

9952711

58.93

54.48

Barbados

42.75

1.53

255203

22.97

53.74

Costa Rica

66.9

1.96

4519126

35.47

53.02

Georgia

44.34

1.58

4307011

23.2

52.33

Romania

30.68

1.35

21513622

15.69

51.14

El Salvador

82.22

2.32

6133910

41.28

50.2

Puerto Rico

52.72

1.8

3954553

25.63

48.61

Chile

59.42

1.93

16803952

28.81

48.49

Venezuela

89.67

2.54

27935000

43.28

48.27

Mauritius

39.77

1.58

1268854

18.63

46.86

Uruguay

60.86

2.01

3334052

28.08

46.14

Top 15 absolute deviation below the trend line

Libya

3.11

2.7

6294181

-47.39

-1523.69

Oman

10.39

3.05

2785361

-45.54

-438.3

Israel

14.15

2.96

7308800

-41.07

-290.26

Djibouti

22.51

3.9

849245

-39.33

-174.7

Samoa

26.77

3.95

178869

-36.17

-135.12

Algeria

7.25

2.36

34373426

-34.7

-478.63

Malaysia

12.66

2.56

27014337

-34.25

-270.55

Uzbekistan

12.83

2.56

27313700

-34.08

-265.64

Micronesia

24.67

3.57

110414

-33.15

-134.39

Jordan

24.33

3.49

5812000

-33.11

-136.09

Saudi Arabia

25.81

3.12

24807000

-30.5

-118.18

Tajikistan

28.07

3.41

6836083

-29.1

-103.68

Qatar

15.81

2.41

1280862

-27.34

-172.93

Tunisia

6.88

2.06

10327800

-27.21

-395.56

France

6.76

2

62277432

-25.75

-380.91

Top 15 percentage deviation below the trend line

Country

Teen births/1,000

TFR

Population

Deviation

% Deviation

Libya

3.11

2.7

6294181

-47.39

-1523.69

Algeria

7.25

2.36

34373426

-34.7

-478.63

Oman

10.39

3.05

2785361

-45.54

-438.3

Denmark

5.92

1.89

5493621

-23.59

-398.55

Tunisia

6.88

2.06

10327800

-27.21

-395.56

France

6.76

2

62277432

-25.75

-380.91

Slovenia

4.84

1.53

2021316

-14.94

-308.59

Sweden

7.58

1.91

9219637

-22.48

-296.58

Israel

14.15

2.96

7308800

-41.07

-290.26

Norway

8.39

1.96

4768212

-23.04

-274.57

Malaysia

12.66

2.56

27014337

-34.25

-270.55

Uzbekistan

12.83

2.56

27313700

-34.08

-265.64

Belgium

7.6

1.82

10708433

-20.02

-263.45

Italy

4.8

1.41

59832179

-11.76

-245

Switzerland

5.44

1.48

7647675

-12.98

-238.69

To restate: my assertion is that nations with a high TFR despite low birth rates in the 15-19 age range indicate a realized preference for large families. This seems to be the class that Israel, Rwanda, and many Middle Eastern nations fall into. Some European nations, such as France, have a higher TFR in relation to what they’re teen birth rates would predict. This is just a function partly of very low teen birth rates. But in the case of France it is probably a function of moderate pro-natalism.

In the other class you have many Latin American nations, whose fertility is modest, but teen birth rates are very high. I think this is probably a symptom of demographic structure within the population. There’s a lot of inequality and variation in economics and cultures within the societies. I think this is why a very low TFR countries such as Romania shows up: the Roma minority has a high teen birth rate. They are not numerous enough to change the average TFR much, but have shifted the teen birth rates.

Mmmm…I think you’re oversimplifying in your interpretation of the data. Just comparing the top 15 percentage over with the top 15 percentage under the trend line:
teen births/1000 TFR
top 15 over
– average 63.4 1.92
– std dev 25.2 0.45
– std dev/avg 0.398 0.233

I include the std dev/avg as a means of comparing the std dev for two samples that are wildly different, especially in the teen births column. The std dev of 25.2 is absolutely larger than a std dev of 3.2, but expressed as a fraction of the average of the sample, for both cases it’s about the same. This implies to me that the scattering within the two samples is roughly the same. Not a sophisticated analysis, I know, but my stats courses were long ago and it’s late. I think this eliminates the possible explanation of random noise in the sample (or, more accurately, indicates that noise levels are roughly the same).

So, if one looks at the countries in each list, the top 15 percentage under list contains countries where society is more settled, conservative and have longer life expectancy…for whatever reason. The countries in the list of top 15 percentage over are countries where there is social upheaval, if not outright violence – and societal controls are less strong and life expectancies are lower. I think a more general explanation is a more basic biological one – reproduce early or you will have no children in the next generation. Yes, I know – how “Selfish Gene” of me. But in this case I think it applies.

http://blogs.discovermagazine.com/gnxp Razib Khan

i think at some point i’ll just try and look into the world bank API and do a lot of comparisons myself.

http://washparkprophet.blogspot.com ohwilleke

“In the other class you have many Latin American nations, whose fertility is modest, but teen birth rates are very high. I think this is probably a symptom of demographic structure within the population.”

A more likely explanation, IMHO, is a predominance of contraceptive sterilization (i.e. vascectomy and tubal ligation) as a birth control method. It is what you would expect if few people were using condoms, IUDs or taking the pill at any age, but if married adult couples were sterilizing once they decided they had enough kids. For example, Brazil has the highest tubal ligation rate in the world.

http://ironrailsironweights.wordpress.com/ Peter

Wouldn’t the low teen birth rates in many Islamic countries be attributable to restrictions on unsupervised contact between young men and women? Of course that doesn’t explain Bangladesh …

http://ukcommentators.blogspot.com/ Laban Tall

Maybe they just marry young in Bangladesh.

Do groups with a high teen birth rate have an “effective” birthrate that’s higher (given that it’s above replacement rate) than a group with identical TFR – because the gap between generations is less ?

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com